Drive mechanism



Dec. 1, 1964 'r. E. LOHR 3,159,045

DRIVE MECHANISM Original Filed April l9,'1957 2 Sheets-Sheet 2 h mvsivrox 1 I! w r gy mymm ATTORNEY 3,159,045 DRIVE MECHANISM Thomas E. Lohr, Detroit, Mich, assignorto General Motors Corporation, Detroit, Mich, a corporation of Delaware Original application Apr. 19, 1957, Ser. No. 653,856, new

Patent No. 3,523,854, dated Mar. 6, 1562. Divided and this application Oct. '11, 1961, 'Ser. No. 144,447 3 Claims. (Cl. 74-411) This invention relates to drive mechanisms, and more particularly to thrust take-up means for gear drive mech-.

'anisms. This application is a division of SN. 653,800,

filed April 19, 1957, now Patent Number 3,023,854.

The axial thrust take-up means of this invention is particularly intended for use with worm and worm wheel drive mechanisms. A primary advantage of the thrust take-up means of this invention is that it accurately positions the worm so that there will be no slippage between the worm and worm wheel while also taking up axial thrust loads in either direction during rotation of the worm.

Furtheradvantages of the thrust take-up means of this invention will be readily apparent from the following specification and drawings'wherein:

FIGURE 1 is a partial side elevational view of a vehicle body having a window drive mechanism mounted thereon embodying a thrust take-up means according to this invention;

FIGURE 2 is an enlarged sectional view taken on the plane indicated by line 22 of FIGURE 1, with parts thereof broken away for clarity of illustration;

FIGURE 3 is a sectional view taken on the plane indicated by line 3-3 of FZGURE 2;

FIGURE 4 is a view taken on the plane indicated by line 4-4 of FIGURE 2;

FIGURE 5 is a sectional view taken on the plane indicated by line 5-5 of FIGURE 4; and

FIGURE 6 is an enlarged sectional view taken on the plane indicated by line 6-6 of FIGURE 4.

Referring now particularly to FIGURE 1 of the drawings, a vehicle 10 includes a windshield 12, a windshield header 14 and a roof 16. A front door 18 is hinged at its forward edge 25 on the vehicle it) for swinging movement between open and closed positions to provide access to the body. A window frame 22 extends upwardly from door 18 to the roof 16 of the body and provides a support for a swingably mounted ventilation window 24 movable between a closed position, as shown, and an open position transverse of frame 22, not shown. The ventilation window is mounted within a frame 26 which is pivotally secured to frame 22 by an upper pivot (not shown) and a lower pivot provided by a window drive shaft 28. The upper and lower pivots define the vertical axis of swinging movement of the window. The drive shaft 28 is rigidly secured to the frame 26 and journaled within door 18 so as to drive the window 24 between open and closed positions upon operation of the window drive mechanism 34).

Referring now to FIGURES 2 through 6 of the drawings, the drive mechanism 36 for the window 24 will be described. A housing 32 includes an upwardly opening vertical bore 34 and a horizontal bore 36 which opens to bore 34 at 38. As may be seen best in FIGURE 3, a worm 46 is positioned within bore 36, with one end 41 of the worm shaft being rotatably supported therein by a plain bearing 42 fixedly secured within bore 36 adjacent one end thereof. The other end 43 of the worm shaft is of reduced diameter and is rotatably mounted within a plain bearing 44 fixedly secured within a reduced portion 45 of bore 36 in engagement with a shoulder 46. A reduced portion 48 of bore 36 immediately 3,155,545 Patented Dec. 1, 1964 "Ice adjacent the reduced portion 45 slidably receives ,a thrust gagement with the end 43 of the worm shaft. A 1ock nut 62 holds the screw 58 in any adjusted position.

As may be seen best in FIGURES 2 and 4, a bracket 64 is bolted at 65 to the housing 32 and includes a spaced pair of laterally extending apertured legs 66. An electric motor 68 is bolted at 7b to each leg 65. A resilient washer 72 is provided on each side of each leg 66 to provide for resiliently mounting the motor on the bracket and also to prevent the vibration of the motor being transferred to the door innerpanel which supports the mechanism 30 as will be described. The armature shaft 76 of the motor terminates in a slotted end 78 which is received within a similar shaped opening on a metal plate 85 to secure the armature of the motor to the plate. Plate 80 is bonded to a circular member 82 of rubber or other elastomeric material to form another portion of the thrust take-up means of this invention. The end 41 of the worm shaft is provided with a bifurcated portion 84- which is received within spaced openings in member 82 to couple the worm to the armature shaft of the motor.

As will be hereinafter described, the worm 40 drives a worm wheel which is part of the gear drive train between the motor 68 and the window drive shaft 28. It is desirable that the worm 40 be held against any axial movement so as to prevent any slippage between the helical thread of the worm and the teeth of the worm wheel. It is alsodesirable that some means be provided to take up axial thrust loads of the worm in either direction. It is further desirable to provide a resilient torsional coupling between the worm and the armature shaft of the motor so that overtravel of the motor will not bend or break any of the parts of the gear drive train when the window has reached a limit position in its movement. 1

The member 82 of rubber or other elastomeric material provides the resilient torsional coupling between the armature shaft of the motor and the worm and takes up any overtravel of the motor when the window has reached a limit position. This member also acts to take up axial thrust of the worm 4% in the one direction towards the armature of the motor. Although the member 82 isof rubber or other elastomeric material, the rubber or other material is of the type which is not readily compressible so as not to be easily compressed under light axial thrust loads. Thus, the member 82 will accurately position the one end 41 of the worm shaft under axial thrust loads in the one direction and will prevent any appreciable axial shifting movement of the worm in the one direction except under heavy axial thrust loads.

The member 52 of nylon or other deformable material acts to accurately position the other end 43 of the worm shaft and to take up any axial thrust loads of the worm in an opposite direction. Since nylon or other materials of this type are not easily deformable, light axial thrust loads do not result in any appreciable axial shifting movement of the worm in this opposite direction except under heavy. axial thrust loads. Thus the combination of the coupling 82 and the member 52 provide a thrust take-up means acting to take up axial 'ing 32.

thrust loads in either direction and to accurately maintain the position of the worm except under heavy thrust loads. The plates 54 and 56 on either side of the member 52 act to distribute the thrust loads of the worm shaft and the load of the adjusting screw 58 uniformly over the member 52 to prevent local deformation.

A worm wheel 95, FTGURE 6, is provided with a central bore 92 having opposite flattened portions receives a shaft 94 having similar opposite flattened portions 56 to rigidly secure the worm wheel to the shaft. The worm wheel meshes with the worm 46 and is driven thereby. Shaft 94 includes an end 93 of reduced diameter which is located and rotatably supported by a plain bearing 188 fixed within a closed boss 102 of hous- In addition, an annular rib 184 on the lower wall of bore 34 of the housing provides a thrust hearing for the worm wheel. A cover 186 fits over the opening of bore 34 and is provided with an apertured boss 188 which opens to bore 34 and a rib 116 which is received within the opening of bore 34 to accurately position the cover in place. A plain bearing 112 mounted within boss 168 locates and rotatably supports the other end of shaft 94 which projects outwardly of the cover.

The cover is bolted to housing 32 at 65 and also at 113.

A plain bearing 114 mounted within an aperture boss 116 of the cover locates and rotatably supports one end 117 of reduced diameter of a mechanism drive shaft 118. The portion 119 of larger diameter of the drive shaft 118 is provided with opposite flattened sides 120 and is received within a central opening of the same shape in a section 122 to secure the sector to the shaft. The sector 122 meshes with a pinion 124 which is fixed to shaft 94. As may be seen best in FIGURE 5, the cover 106 is provided with an upwardly extending lug 125 adjacent the boss 116. The circumferentially spaced shoulders 126 of the sectorare engageable with opposite sides of the lug to act as limit stops fixing the limit positions of the window.

As may be seen best in FIGURES 2, and 6, U-shaped bracket 128 bolted to the housing 32 at 65 and 113 is provided with a flanged opening 130 which rotatably receives and locates the enlarged end 132 of shaft 118. A washer 134 is provided with a central opening of the shape of portion 119 of shaft 118 so as to be fixed thereto. A Belleville spring 136 is slidably and rotatably mounted on portion 119 of shaft 118 and has its outer and inner edge portions under compression against bracket 128 and washer 134, respectively. The bearing spring provides a frictional coupling between the shaft 118 and the drive mechanism housing through bracket 128 so as to frictionally hold the shaft in any rotative position as will be further described.

Since the Belleville spring 136 does not frictionally bear against the shaft 118, there is no possibility of undue wear of the shaft. In addition, it will be noted that only the inner and outer edge portions of the spring bear'against the washer 134 and the bracket 128 respectively, so that the immediate area of contact between any portion of the edge portions of the spring and either the bracket or washer 134 is relatively small. However, the total area of frictional engagement is rather large. In addition, since these total areas of engagement of the inner and outer edge portions of the spring 136 are concentrically located, a more effective frictional force is provided to hold the shaft 118 in any rotative position thereof.

Referring now particularly to FIGURES 2 and 6 of I the drawings, the enlarged end 132 of shaft 118 is provided with a cruciform shaped slot 148. A generally U-shaped spring clip 142 fits within opposite legs of the slot 146 and conforms substantially to the contour of the slot hetween these legs, as may be seen particularly in FIGURE the extremity of these legs defining an opening of less width than the width of the opposite legs of the slot 140 receiving the spring clip. In addition, the legs 146 join each of the legs 144 on a curved juncture so that the legs 146 may be wedged between the opposite side walls of each of the opposite legs of slot 148 to additionally hold the clip in place.

As shown best in FIGURE 2 of the drawings, the lower end of the window drive shaft 28 is flattened to provide a flattened end portion 158 which is slightly larger than the openings defined by the convering legs 146 of the spring clip so as to be wedgingly received between the opposite pairs of legs. Since the legs 146 are resiliently connected to each of the legs 144, it is not necessary for the window drive shaft 28 to be axially aligned with the mechanism drive shaft 118, since the legs 146 will take up any misalignment between the shafts. In addition, as will be described, the drive mechanism 30 is fixedly mounted on the door inner panel below the window 24 and the lower end of the window drive shaft 28 may not terminate exactly at the base of the clip 142, as indicatedin FIGURE 6. However, even under such conditions, the spring clip will still provide a driving connection between the mechanism drive shaft 118 and the window drive shaft 28. Thus there is no need for any substantial adjustment of the window drive mechanism 30 relative to the shaft 28 in order to adequately establish a driving connection between the shaft of the mechanism.

As best seen in FIGURES 5 and 6, an angular mounting bracket 151 includes a pair of laterallyxextending spaced legs 152 which receive the boss 182 of housing 32 therebetween and are bolted at 65 and 113 to the drive mechanism. The mounting bracket 151 further includes a number of threaded bosses 154 which extend laterally thereto and are adapted to bear against the inner panel 156 of door 18, as best shown in FIGURE 2. Bolts 158 which extend through apertures in the inner panel and are threaded within bosses 154 mount the drive mechanism on the door in a unitary assembly.

It will be noted that the component parts of the drive mechanism are secured together solely by the bolts 65 and 113 so that the assembly may be easily disassembled into its component parts without necessarily removing the entire unit from the door 18. If replacement or repairs are required for the motor 63, removal of the bolts 76 allows the motor to be'detached from the assembly. If any repairs are needed internally of the mechanism, removal of the bolts 65 and 113 allow the entire drive mechanism to be easily disassembled without removing the mounting bracket 150 from within the door.

Since the operation of the drive. mechanism is believed to be apparent from the foregoing description, only a brief description of the operation will be given. Upon operation of the motor 68 in the required direction, the worm 49 will drive the worm wheel and in turn rotate the shaft 94. As the shaft 94 rotates, the pinion 124 will drive the sect-ion 122 and in turn drive the mechanism drive shaft 118. The mechanism drive shaft will then drive the window drive shaft 28. When the window has reached a limit position, the engagement of either of the shoulders 126 of the sector 122 with lug will fix the limit positions of the window. When the window is in any stationary position, the Belleville spring 136 will act to prevent any forcible movement of thewindow to another position by the operator or other persons. In addition, since the window 24 may be disposed in one or more open positions transversely of the opening of frame 22, the Belleville spring 136 will act to hold the window in this position against any wind resistance caused by movement of the vehicle.

Thus this invention provides an improved thrust take-up means for drive mechanisms.

What is claimed is:

1; In a'drive mechanism, the combination comprising, a housing having a bore therein, a shaft rotatably mounted in said bore and axially shiftable therein, means in said bore providing an abutment located in axially spaced relationship to one end of said shaft, a thrust takeup member positioned within said bore between said abutment and said one end of said shaft and norm-ally spacing said one end of said shaft with respect to said abutment, said takeup member including a member of deformable plastic material, said deformable member being deformed by axial thrust loads of a predetermined magnitude applied in one direction by said one end of said shaft to said thrust takeup member to take up such loads, power operating means, and a resilient member coupling said power operating means and the other end of said shaft, said resilient member locating said other end of said shaft and taking up axial thrust loads applied thereto by said shaft in an opposite direction. 7

2. A drive mechanism as recited in claim 1 wherein said thrust takeup member includes substantially rigid end members located to each side of said member of ment and said one end of said shaft to equally distribute 6 over said deformable member the axial thrust loads applied by said one end of said shaft.

3. A drive mechanism as recited in claim 2 wherein the area of said end members opposing said abutment and said one end of said shaft is greater than the opposing areas of said abutment and said one end of said shaft respectively.

References Cited in the file of this patent UNITED STATES PATENTS 1,323,850 Fisher Dec. 2, 1919 1,534,762 Bostick Apr. 21, 1925 1,769,374 Kutter July 1, 1930 2,317,490 Simpson Apr. 27, 1943 2,571,267 Ljunggren Oct. 16, 1951 2,586,293 Birkigt Feb. 19, 1952 2,688,883 Schut Sept. 14, 1954 2,720,764 Landrum Oct. 18, 1955 FOREIGN PATENTS 673,852 France Jan. 21, 1930 

1. IN A DRIVE MECHANISM, THE COMBINATION COMPRISING, A HOUSING HAVING A BORE THEREIN, A SHAFT ROTATABLY MOUNTED IN SAID BORE AND AXIALLY SHIFTABLE THEREIN, MEANS IN SAID BORE PROVIDING AN ABUTMENT LOCATED IN AXIALLY SPACED RELATIONSHIP TO ONE END OF SAID SHAFT, A THRUST TAKEUP MEMBER POSITIONED WITHIN SAID BORE BETWEEN SAID ABUTMENT AND SAID ONE END OF SAID SHAFT AND NORMALLY SPACING SAID ONE END OF SAID SHAFT WITH RESPECT TO SAID ABUTMENT, SAID TAKEUP MEMBER INCLUDING A MEMBER OF DEFORMABLE PLASTIC MATERIAL, SAID DEFORMABLE MEMBER BEING DEFORMED BY AXIAL 